System and method for charging carbon dioxide containers



March 2, 1954 V ZANDT SYSTEM AND METHOD FOR CHARGING CARBON DIOXIDE CONTAINERS Filed May 7, 1951 INVENTGRS HARVEY Vq/vZA/vzw A/vo AAT/IURA. 555M:

ATTORNEY Patented Mar. 2 1954 SYSTEM AND METHOD FOR CHARGING CARBON DIOXIDE CONTAINERS Harvey Van Zandt, Whippany, and Arthur A. Sesnie, Hoboken, N. J., assignors to C-O-Two Fire Equipment Company, Newark, N. J a corporation of Delaware Application May 7, 1951, Serial No. 224,901

7 Claims.

The present invention relates to a system for and a method of charging a carbon dioxide storage container from a low temperature supply. The storage container may be part of a fire extinguisher utilizing carbon dioxide as the extinguishing agent.

Heretoiore in charging such a storage container or cylinder it generally has been the practice to pump the carbon dioxide from a supply tank into the container to be charged, sufficient pressure being provided by the pump to fill the container to its desired capacity. For use as a fire extinguisher it is generally the practice to fill the cylinder to not over 68% of its water capacity by weight, the. ratio being the weight of carbon dioxide to the water capacity by weight of the cylinder.

At a temperature of 80 F. the pressure in the cylinder will be approximately 1,000 pounds per square inch while if the temperature is lowered 50 F. the pressure in the cylinder will drop to about 600 pounds per square inch. Thus it is obvious that the pump must be capable of providing a high pressure adequate to charge the cylinder to the required weight. By reason of the high pressure required the pumps are necessarily expensive .in construction and maintenance.

The present invention provides a system and method of charging carbon dioxide storage containers without the use of a pump by utilizing changes in the vapor pressure of carbon dioxide stored in an intermediate vessel for forcing the requisite amount of fluid into the container being charged. The variation in vapor pressure is obtained by heating the carbon dioxide.

An object of the invention is to provide a system for charging carbon dioxide storage containers which is inexpensive in construction, efficient in operation and durable in use.

Another object of the invention is to provide a method of charging carbon dioxide storage containers which is simple and inexpensive to perform.

In accordance with the invention this is accomplished by providing an insulated supply tank for carbon dioxide which is adapted to be refrigerated so that the carbon dioxide is stored at a low pressure, thus permitting the use of a tank of inexpensive construction. It has been found that at the preferred temperature of 0 F. the vapor pressure of the carbon dioxide will be approximately 300 pounds per square inch, as against a pressure of 1,000 pounds at 80 F., or a pressure of 2.000 pounds at 120 F. The system is advantageous in thatit may be made portable and transported to any desired location for the charging of the storage vessels without the necessity of providing for a source of power such as required in operating a pump.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawing which shows, by way of example, an embodiment of the invention.

In the drawing is shown a schematic layout of a system for charging carbon dioxide storage containers in accordance with the invention.

Referring to the drawing, a tank I is provided to receive a supply of carbon dioxide. A manhole cover 2 is provided at the end of the tank for charging with solid carbon dioxide if desired, and to provide a means of entry into the tank for inspection or cleaning. In addition, a liquid filling pipe 3 with a shut-01f valve 4 and a vapor release line 311 with a shut-off valve 4a are provided to receive liquid carbon dioxide. The tank I is suitably insulated as indicated at 5 to retard the absorption of heat through the wall of the tank. A refrigeration compressor I is connected by pipes 9 and I0 to an expansion coil II positioned within the tank I to remove heat which may leak into the tank through the insulation 5. The tank I is preferably supported on a platform I2 or mounted at a higher elevation than the remainder of the apparatus in order to provide for a gravity flow of the carbon dioxide as will later appear.

A pair of intermediate storage vessels'III and I5 are connected to the supply tank I by a pipe I6 entering at the bottom of the tank I and feeding into the bottom ends of the intermediate tanks I i'and I 5. The supply tank outlet is fitted with a valve I'I while the inlets to the tanks I4 and I5 are respectively closed by valves I9 and 20. The inlet to the supply tanks I4 and I5 are T-tapped as indicated at 2i and 22 to provide for connections to blow-off pipes 24 and 25 closed by valves 26 and 21.

From the upper portions of the intermediate tanks I4 and I5 pipes 28 and 29 lead through valves SI and 32 and connecting pipes 33 and 34 to a manifold 35 entering the top of the tank I and terminating in the vapor space of the tank. The manifold 35 is T-tapped as indicated at 36 to provide a connection for a blow-off line 31 closed by a valve 38. A shut-off valve 39 is provided in a connection to the vaporspace of the tank I.

Outlets for liquid carbon dioxide from the intermediate tanks I4 and I5 are provided by pipes 40 and H each extending to the bottom of its tank, each being closed by a valve 42 and a valve 43 and T-tapped at 44 to an outlet line 45 which may be a flexible conduit or a suitable piping system. A connection fitting 46 is positioned at the end thereof and fitted with a flexible charging conduit 4'! for attachment to a storage container 48 to be charged.

The intermediate vessels I4 and I5 are of a construction to withstand a greater pressure than the supply tank I and are used to hold carbon dioxide from the supply tank i while its vapor pressure is increased by the addition of heat to increase the vapor pressure the required amount to charge the supply container with liquid carbon dioxide. Any suitable means may be used to add heat to the carbon dioxide in the tanks I 4 and I5 such as by the use of an electric heating coil or by providing direct means for heating the walls of the intermediate tanks by the use of a flame or other suitable means, or by the use of a water jacket or enclosing tank in which the heating liquid may be placed. An economical construction is shown in which perforated ring pipes 50 and 5| are positioned respectively about the upper portions of the vessels I4 and 15 so as to spray the surface of the vessels with a hot liquid such as water the heat from which is transmitted through the walls of the vessel to heat the carbon dioxide. It has been found that by reason of the comparatively low specific heat of the carbondioxide that a small amount of heat will provide a suificiently increased vapor pressure for practical purposes without appreciably raising the temperature of the body of liquefied carbon dioxide temporarily stored in the intermediate tank. Hot water or other heated liquid is supplied from a source (not shown) through a pipe 52 having individual leaders 54 and 55 controlled by valves 58 and 5'! for the perforated ring conduits 50 and EI. If desired, in order to collect the waste hot water or other liquid drip pans E and 6| may be respectively positioned at the bottom of the tanks I4 and I and connected through pipes 62 and 63 to a suitable the supply tank I cooling means are provided comprising perforated ring pipes II and 12 respectively connected through leaders I3 and I4 controlled by valves I5 and 76 supplied with a cooled liquid such as from a cold water line I1. Alternatively, a water jacket or enclosing tank may be used as was described in connection with the means for heating the carbon dioxide.

In operating a system in accordance with the invention, the supply tank I is provided with liquid carbon dioxide either by loading it with solid carbon dioxide through the manhole 2 or by loading it with liquid carbon dioxide through the inlet 3. The carbon dioxide is maintained at a desired substantial constant sub-ambient temperature by means of the refrigerating compressor I which is automatically controlled to maintain the stored carbon dioxide at the desired temperature. The intermediate tanks I4 and are preferably alternatively used, that is, While one is being filled the other may be used for charging storage vessels, and vice versa. In filling the intermediate vessel [4 the valves I1 and I9 are opened as are valves 1-H and 39 so that liquid carbon dioxide may flow under the action of gravity through the pipe it into the intermediate vessel I4, the displaced vapor being exhausted through the manifold 35 to the vapor space of the supply tank I where it is again condensed to liquid. Alternatively the valve 39 may be closed and the valve 38 opened to allow the displaced carbon dioxide to escape to the atmosphere. After the required amount of carbon dioxide has been let into the intermediate tank I4 the valves I 9 and SI are closed and hot water valve 51 is opened to warm the carbon dioxide in the tank. After the carbon dioxide has been warmed enough to increase its vapor pressure to the desired amount, the hot water supply is shut off as it has been found that ample pressure will be maintained by reason of the heat in the ambient air.

In charging a storage vessel it is connected to the charging conduit and the valve 42 opened whereupon the vapor pressure in the vessel I4 expel the liquid therefrom through pipes 40, and 41 into the container 48 being charged.

Intermediate vessel I5 may be charged in like manner by opening its valves 20 and 32 to let in the required amount of refrigerated carbon dioxide liquid whereupon these valves are closed and hot Water valve 56 is opened to provide the heat to increase the vapor pressure of the carbon dioxide. The contents of the intermediate container I5 are discharged through valve 43.

After the liquid carbon dioxide has been practically completely discharged from either of the intermediate vessels I4 or I5, the pressure of the vaporous carbon dioxide is lowered by cooling with cool water admitted from valve I5 or valve it to the perforated rings II or 12. It has been found that suflicient cooling is achieved by use of tap water at its normal temperature. The supply of carbon dioxide in the intermediate tanks I4 or I 5 may then be replenished by opening the valves to the supply tank i and the cycle of operation repeated.

From the preceding description it will be seen that the present invention provides a simple and economical system for and method of charging carbon dioxide containers and which eliminates the use of a pump.

While the invention has been described and illustrated with reference to a specific embodiment thereof, it will be understood that other embodiments may be resorted to without departing from the invention. Therefore, the form of the invention set out above should be considered as illustrative and not as limiting the scope of the following claims.

We claim:

1. The method of charging a storage vessel with carbon dioxide comprising maintaining a source of supply of liquid carbon dioxide at a substantially constant sub-ambient temperature and its corresponding vapor pressure, transferring liquid carbon dioxide from the source of supply to an intermediate storage vessel under theaction of gravity while allowing vaporous carbon dioxide to flow from the intermediate storage vessel to the source of supply, confining the carbon dioxide in the intermediate storage vessel while applying heat to the carbon dioxide to increase its vapor pressure, transferring carbon dioxide from the intermediate vessel under its own vapor pressure to charge the storage container, and withdrawing heat from the remaining carbon dioxide in the intermediate storage vessel to lower the vapor pressure of the confined carbon dioxide so that the intermediate vessel may receive additional carbon dioxide fro the source.

2. The method of charging a storage container with carbon dioxide comprising maintaining a refrigerated source of supply of carbon dioxide at a substantially constant sub-ambient temperature and its corresponding vapor pressure, transferring liquid carbon dioxide from the source of supply to an intermediate storage vessel under the action of gravity while allowing vaporous carbon dioxide to flow from the intermediate storage vessel to the source of supply, confining the carbon dioxide in the intermediate storage vessel while applying heat to the storage vessel by passing a heated liquid over the surface of the intermediate vessel to increase the vapor pressure of the confined carbon dioxide, transferring carbon dioxide from the intermediate vessel under its own increased vapor pressure to charge the storage container, and withdrawing heat from the remaining carbon dioxide in'the intermedaite storage vessel by passing a cold liquid over the surface of the intermediate vessel to lower the vapor pressure of the confined carbon dioxide so that the intermediate vessel may receive additional carbon dioxide from the source.

3. A system for charging a storage container with carbon dioxide comprising an insulated tank for confining a supply of carbon dioxide, refrigerating means for maintaining liquid carbon dioxide in the supply tank at a substantially constant sub-ambient temperature and corresponding vapor pressure, means to support the insulated tank in an elevated position, an in- I termediate vessel to receive liquid carbon dioxide from the supply tank and positioned at a lower level than the supply tank to receive carbon dioxide therefrom by gravity flow, a fluid connection from the supply tank below its liquid level to the intermediate vessel, a fluid connection from the intermediate vessel vapor space to the supply tank vapor space, valve means in said fluid connections, a valved outlet for the intermediate vessel to connect to a storage container for the charging thereof, and heating means to increase the vapor pressure of carbondioxide in the intermediate vessel to the desired pressure to charge the storage container.

4. A system for charging a storage container with carbon dioxide comprising an insulated tank for confining a supply of carbon dioxide, refrigerating means for maintaining liquid carbon dioxide in the supply tank at a substantially constant sub-ambient temperature and corresponding vapor pressure, means to support the insulated tank in an elevated position, an intermediate vessel to receive liquid carbon dioxide from the supply tank and positioned at a low-er level than the supply tank to receive carbon dioxide therefrom by gravity flow, a fluid connection from the supply tank below its liquid level to the intermediate vessel, a fluid connection from the intermediate vessel vapor space to the supply tank vapor space, valve means in said fluid connections, a valved outlet for the intermediate vessel to connect to a storage container for the charging thereof, a supply of heated liquid, and a perforated ring connected to the heated liquid supply and positioned about the intermediate vessel to increase the vapor pressure of carbon dioxide in the intermediate vessel to the desired pressure to charge the storage container.

5. A system for charging a storage container with carbon dioxide comprising an insulated tank for confining a supply of carbon dioxide, refrigerating means for maintaining liquid carbon dioxide in the supply tank at a substantially constant sub-ambient temperature and corresponding vapor pressure, means to support the insulated tank in an elevated position, an intermediate vessel to receive liquid carbon dioxide from the supply tank and positioned at a lower level than the supply tank to receive carbon dioxide therefrom by gravity flow, a fluid connection from the supply tank below its liquid level to the intermediate vessel, a fluid connection from the intermediate vessel vapor space to the supply tank vapor space, valve means in said fluid connections, a valved outlet for the intermediate vessel to connect to a storage container for the charging thereof, hot water means to increase the vapor pressure of carbon dioxide in the intermediate vessel to the desired pressure to charge the storage container, and cooling liquid supply means to lower the vapor pressure of carbon dioxide in the intermediate vessel to the desired pressure so that the carbon dioxide may be replenished by gravity flow from the supply tank.

HARVEY VAN ZANDT. ARTHUR A. SESNIE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,629,174 Patton May 17, 192 1,738,233 Conill Dec. 3, 1929 1,808,618 Trezise June 2, 1931 2,059,942 Gibson Nov. 3, 1936 2,487,863 Garrettson Nov. 15, 1949 

